How to Fix a Wobbly Toilet

Find out the most common cause of a wobbly toilet, and get tips on using a flange repair kit to solve the problem. Also learn how to reset a flange at the right height.

LESLIE: Well, we’ve all been there. You’re sitting on your commode minding your own business and suddenly you are caught off-guard by a movement that you were absolutely not expecting. (Tom laughs) And I’m not talking about your stomach here. I’m talking about a wobbly toilet.

TOM: Well, it’s a common problem. It’s actually not too difficult to fix. Here to tell us exactly how to do just that are our friends Kevin O’Connor[1], host of This Old House[2], and the program’s plumbing expert, Richard Trethewey[3].

Welcome, guys. Where do we begin?

KEVIN: Most toilets sit on a very small base. This small footprint allows you more space in a bathroom and it makes it easier to clean. Unfortunately, it can also mean that if the toilet is not properly installed, it can wobble.

RICHARD: Right. Now, underneath the toilet, there is a flange. Now this flange is designed to hold the toilet and connect it down to the drain pipe that sits below the floor. Now, oftentimes, wobbly toilets are caused by a broken or cracked flange. Now, you can simply pull the toilet up and install a flange repair kit and sometimes that will fix it. Now other times, the problem is that the flange is actually installed too high. Now some people would put little shims underneath the toilet to try and hold it at the right height but I would much prefer to reset the flange[4] at the exact correct height.

KEVIN: But resetting the flange, especially if it’s cast iron, is a pretty big job.

RICHARD: It can be; you know, if you have to pour a new lead and oakum joint like we have done for 100 years. But sometimes, instead, I’ll use a compression flange that can be secured right to the floor.

KEVIN: Alright. And we’ve got step-by-step videos of repairing and replacing a closet flange on ThisOldHouse.com.

TOM: And those wobbly toilets can actually develop into leaks that end up rotting out the floor, huh?

RICHARD: Right, we often see that; that a wobbly toilet gets ignored and sooner or later you have to go back and rebuild the entire bathroom floor.

TOM: So a wobbly toilet doesn’t mean you just need to go lose some weight.

RICHARD: No, no, no. And you don’t want to ignore it because it never gets better.